Basic question on selection numbers

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In summary, the probability of selecting an odd digit is $\frac{3}{5}$ on the first selection and $\frac{3}{5}$ on the second selection, resulting in a total probability of $\frac{3}{10}$ after three selections.
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karush
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1.1 Among the digits 1,2,3,4,5 first one is chosen, and then a second selection is made among the remaining four digits. Assume that all twenty possible results have the same probability.
Find the probability that an odd digit will be selected. $\frac{3}{5}$ The second time $\frac{3}{5}$ The third time $\frac{3}{10}$
my question on this was how do they get 20 possible results on if one odd is taken away after the selection, and did not understand how $\frac{3}{10}$ was derived? thanks ahead...:cool:
 
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The 20 possible results are 1-2, 1-3, 1-4, 1-5, 2-3, 2-4, 2-5, 3-4, 3-5, 4-5. For each of these combinations, there is a probability of $\frac{3}{5}$ that an odd digit will be selected. This gives us a total probability of $\frac{3}{5} \times \frac{3}{5} \times \frac{3}{10} = \frac{3}{10}$.
 

FAQ: Basic question on selection numbers

What are selection numbers?

Selection numbers refer to the process of choosing a specific number of individuals or items from a larger group for a particular purpose or study.

Why are selection numbers important in science?

Selection numbers are important in science because they ensure that the chosen sample is representative of the larger population, helping to draw accurate conclusions and make generalizations about the entire group.

How are selection numbers determined?

The determination of selection numbers depends on various factors such as the size of the population, the level of variation within the population, the desired level of accuracy, and the research question being investigated. Statistical methods and sampling techniques are often used to determine the appropriate selection numbers.

What is the difference between random and non-random selection numbers?

Random selection numbers involve choosing individuals or items from a population at random, without any particular criteria. This helps to minimize bias and ensure a representative sample. Non-random selection numbers, on the other hand, involve choosing individuals or items based on specific criteria, such as age, gender, or location.

What are some challenges in determining selection numbers?

Some challenges in determining selection numbers include limited resources, time constraints, and the complexity of the population being studied. It can also be difficult to determine the appropriate level of accuracy and representativeness needed for the study.

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